Two-ring action camera shutter



June 24, 1952 J. E. HENRY 2,501,236

TWO-RING ACTION CAMERA SHUTTER Filed July 5, 1951 2 SHEETS-SHEET 1 INVENTOR. 44/1/55 5 0149 LUAA Wine/Yer;

June 24, 1952 J. E. HENRY TWO-RING ACTION CAMERA SHUTTER 2 SHEETS-SHEET 2 Filed July 5, 1951 INVENTOR.

i-lll Patented June 24, 1952 UNITED STATES PATENT OFFICE TWO-RING ACTION CAMERA SHUTTER James E. Henry, Dayton, Ohio Application July 5, 1951, Serial No. 235,355

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 4 Claims.

The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to me of any royalty thereon.

This invention relates to shutters for photographic cameras and particularly to shutters of the type wherein a spring actuated mechanism is tensioned and released to make an exposure.

The shutter herein shown differs from the known art in a novel mechanism which provides to a greater degree than heretofore known, slow starting, fast opening, fast closing and a slow stopping of the shutter, a feature of much importance in a camera shutter.

Other novel features and advantages will be apparent from a consideration of the following specification, reference being had to the drawing, wherein:

Fig. 1 is a top plan view of the improved shutter, parts being broken away for clearness.

Fig. 2 is a fragmentary bottom plan view of the drive arms of the shutter mechanism.

Fig. 3 is another top plan view with parts broken away to a different level than shown in Fig. 1.

Fig. 4 is a vertical section taken at 4-4 of Fig. 1.

Fig. 5 is a fragmentary vertical section through the winding mechanism.

Fig. 6 is a cross section taken at 6-6 of Fig. 5 through the trip cam and pawl of the winding mechanism.

The embodiment of my invention shown in the drawings comprises a mounting plate I having a winding unit I2 fixed on the upper side and a shutter blade assembly I4 fixed on the underside.

The winding unit I2 comprises a cylindrical case I6 with a large flange I8 at the lower end and a cover 20, the flange and cover being spaced apart from the mounting plate II) by tubular spacers 22 through which screws 24 pass to threadedly engage the mounting plate I0.

Within the casing I6 the shaft 26 of a double throw crank is rotatable. An inverted cup 28 (see Fig. has an elongated hub 38 which has rotative hearing at 32 in the casing I6. Elongated hub 30 has a central opening 34 within which the upper end of shaft 26 has rotative bearing. A thumb nut 36 has a one toothed ratchet 38 integral therewith, the nut and ratchet being joined by a neck 39 and fitted snugly over the hub 30 and fixed thereto by a pin 48. A small plunger 42 is urged radially inward by a spring 44 to act as a pawl to engage the one 2 toothed ratchet. Plunger 42 is slidable in a lug 43 which is integral with the cylinder I6.

Near the lower end of the cylindrical casing I6 (see Fig. 4) a cup 46 is fixed on the shaft 26 by a pin 48. Cups 28 and 46 are .slotted as at 50 and 52 to receive the outturned ends 54 and 56 of a spring 58 which supplies the energy for rapid opening and closing of the shutter I4. A length of tubing 59 keeps the spring 54 concentric with the axis of the shaft 26.

The trip mechanism for releasing the spring 58 consists of a disc 60 fast on the shaft 26. A lug 62 may preferably be cut integral with the disc 69. A latch 64 is pivoted on the plate I0 at 66.

A trip lever 68 is pivoted on the plate In at 10. Trip lever 68 carries a lug I2 which engages the lug 62 to prevent rotation of the disc 60 and shaft 26 while winding is being effected. A heavy spring 14 yieldably holds the latch 64 against the disc 60. p A relatively light spring I6 yieldably holds the lug I2 in engagement with the lug 62 so that the thumb nut 36 may be turned a complete turn until caught by the pawl or plunger 42 while the crankshaft 26, which carries the disc 60 and lugs 62 and I2, remain engaged until tripped by the trip lever 68.

At its extreme lower end, the shaft 26 is provided with a two-throw crank composed of two discs I8 and axially spaced as at 82 and provided with crank pins 84 and 86 spaced circumferentially one hundred eighty degrees. Drive arms 88 and 90 have their operating ends pivoted on crank pins 84 and 86 respectively.

The foregoing description relates to the shutter operating mechanism. The shutter itself will now be described.

Located on the underside of the mounting plate I0 are two concentric discs 92 and 94, axially spaced apart by washers 96 and held to the mounting plate by screws 98. The upper disc 92 is of uniform thickness throughout and has a central opening I00 to admit the light rays when the shutter blades are operated through open position. A series of four arcuate shutter operating slots I02 extend through disc 92 and are circumferentially equally spaced in concentric relation to said light opening I00. A second series of shutter operating slots I04 are circumferentially equally spaced in concentric relation to said light opening I00 but are radially further from the center of the disc than the first series.

The lower disc 94 has a central light opening I86 substantially like the opening I80 in the upper disc 92 but has a short upwardly extending hub I08 concentrically surrounding the opening. A small ring H is rotatably fitted over the hub I08 and a larger ring H2 is concentric with and rotatable on the small ring IIO. Four circumferentially equally spaced pins II4 extend upward from the face of the small ring I I0. Four circumferentially equally spaced pins H5 extend upward from the face of the large ring i I2. There are four single end shutter blades I I8 each having a round opening I which fits over one of the pins I I4, and has a slot I22 into which one of the pins I I6 extends and may move from one end of the slot I22 to the other end.

An arcuate window I24 is cut through the lower disc 94 (see Fig. 2). Wrist pin pads I26 and I28, fast on inner ring H0 and outer ring I I2 respectively, extend through and slightly beyond this window. The lower pad I28 carries a wrist pin I30 While the upper pad I26 carries a bracket I 32 which in turn carries a wrist pin I343. Bracket I32 positions the Wrist pin I34 far enough out to permit the drive arms 88 and 3G to rock between the bracket I32 and the pad I28. By making the distance between the center of pin I30 and the center of pin I34 equal to the throw of the double-throw crank, i. e., the distance between the centers of the crank pins 84 and 86, the turning of the crank through one hundred eighty degrees places the pin I30 where the pin I34 was and places the pin 34 where the pin I30 was. When the crank turns on to three hundred sixty degrees, the pins I30 and I34 will be back to their normal positions as shown in Fig. 2, and the shutter mechanism will have opened and closed.

The shutter has the advantage that exposure will be slow starting, fast opening, fast closing and slow stopping. The crank starts its 360 degree turn. The drive arms 88 and 90 move very slowly in a line along their axes at the beginning of the turn but accelerate to a maximum speed at 90 degrees. When the two drive arms have been moved a distance equal to 90 degrees rotation of the two throw crank, the pins in the inner and outer rings are at a minimum distance apart and the shutter blades are moving at their maximum speed. At this point the blades start opening and since they are moving at maximum speed the shutter opens very fast. The blades decelerate from maximum to zero while the crank rotates from 90 to 180 degrees and then accelerates to maximum speed while the crank turns from 180 to 270 degrees, at which point the blades are again traveling at maximum speed andare closing, whereby the shutter closes very fast. At approximately 27 5 degrees the shutter is closed.

It is noted that the herein disclosed shutter differs from the known art in that the pivots of the blades move as well as the pins which drive the blades around the pivots.

The shutter has a theoretical efficiency of 91 and with the lens wide open and approximately 97 and /29.; efficient at F 16 in a 6 inch focal length camera. This is far above any camera shutter in Air Force cameras. Moreover, it may be fabricated so that it will go between the lens without disturbing the elements.

I claim:

1. A slow starting, fast opening, fast closing and slow stopping camera shutter which comprises, a mounting plate, upper and lower discs carried on the underside of said mounting plate, means to maintain said discs in axially spaced apart relation, a concentric hub fast on the upper side of said lower disc, an inner ring freely rotatable on said hub, an outer ring freely rotatable on said inner ring, a number of radially equal circumferentially equally spaced pins extending upwardly from the inner ring, an equal number of radially equal circumferentially equally spaced pins extending upwardly from the outer ring, an equal number of single end shutter blades each having a pivotal opening to fit over one of the inner ring pins, and a slot to fit over one of the outer ring pins, the inner end of a slot being at most as far from the pivot pin as the difference between a radius of an inner ring pin and a radius of an outer ring pin, and the outer end of the slot being at least as far from the pivot pin as the ring pins are apart when at maximum opposite rotation of said rings, and said upper disc having a like number of circumferentially equally spaced slots corresponding radially to the outer ring pins, and a like number of circumferentially equally spaced slots corresponding radially to the inner ring pins, said outer and inner ring pins projecting upwardly through said upper disc slots, ring-rocking wrist pins extending one from each ring through an arcuate window in the lower disc, a two-throw crank rotatably mounted on said mounting plate with axis normal to said plate, drive arms connecting the crank pins one to each wrist pin, and a winding mechanism having spring means adapted to store energy for operating said shutter blades, and latch meansto release said energy and turn said two-throw crank through three hundred sixty degrees to a stop.

2. In a slow starting, fast opening, fast closing and slow stopping camera shutter, axially spaced upper and lower discs, a concentric hub on the upper side of said lower disc, an inner ring freely rockable on said hub, an outer ring freely rockable on said inner ring, a circular row of a number of equally spaced pins extending upwardly from the inner ring, a circular row of a like number of equally spaced pins extending upwardly from the outer ring, a like number of single end shutter blades each having a pivotal opening to fit over one of the inner ring pins and a slot to fit over one of the outer ring pins, the inner end of a slot being at most as far from the pivot pin as the difierence between a radius of an inner ring pin and a radius of an outer ring pin, and the outer end of the slot being at least as far from the pivot pin as the ring pins are apart when at maximum opposite rocking of said rings, and said upper disc having a like number of circumferentially equally spaced slots corresponding radially to the outer ring pins, and a like number of circumferentially equally spaced slots corresponding radially to the inner ring pins, said outer and inner ring pins projecting upwardly through said upper disc slots, members including wrist pins extending one from each ring through an arcuate window in the lower disc, a rotatable two-throw crank, drive arms connecting said crank pins one to each' wrist pin, and means to rotate said two-throw crank through three hundred sixty degrees.

3. A camera shutter which comprises axially spaced apart upper and lower plates, a hub fast on the upper side of said lower plate, an inner ring freely rotatable on said hub, an outer ring freely rotatable on said inner ring, a circular row of equally spaced pins extending from the inner ring, a similar row of equally spaced pins extending from the outer ring, a like number of shutter blades each having a pivotal opening to fit over one of the inner ring pins, and a slot to fit over one of the outer ring pins, the inner end of a slot being at most as far from the pivot pin as the difference between a radius of an inner ring pin and a radius of an outer ring pin, and the outer end of the slot being at least as far from the pivot pin as the ring pins are apart when at maximum opposite rotation of said rings, and said upper plate having a like number of circumferentially equally spaced slots corresponding radially to the outer ring pins, and a like number of circumferentially equally spaced slots corresponding radially to the inner ring pins, said outer and inner ring pins projecting through said upper plate slots, rocking pins extending one from each ring, a two-throw crank,

drive arms connecting the two-throw crank pins one to each rocking pin, and means to rotate said two-throw crank.

4. A two ring action camera shutter which comprises, two concentrically supported independently rotatable rings one within the other, a circular row of equally spaced pins extending axially from the inner ring, a circular row of a like number of equally spaced pins extending axially from the outer ring, a number of shutter blades corresponding to the number of pins in each of said rows, each blade having a pivotal opening to fit over one of the inner ring pins, and a slot to fit over one of the outer ring ins, the

inner end of a slot being at most as far from the pivot pin as the difference between a radius of 6 an inner ring pin and the radius of an outer ring pin, and the outer end of the slot being at least as far from the pivot pin as the ring pins are apart when at maximum opposite rotation of said rings, an upper plate having a number of circumferentially equally spaced slots corresponding in number to the number of pins in each row, and corresponding in position to the radius of the outer ring pins, and a like number of circumferentially spaced slots corresponding radially to the inner ring pins, said outer and inner ring pins projecting through said upper plate slots, two rocking pins extending downward, one from each ring, a two bearing crank, connecting rods joining the crank pin hearings to the two rocking pins, and means to rotate said crank.

JAMES E. HENRY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,166,921 McPhee Jan. 4, 1916 2,168,893 Aiken Aug. 8, 1939 2,398,409 Carroll Apr. 16, 1946 2,448,876 Fuerst Sept. '7, 1948 

